1. Field of the Invention
The present invention relates to a rotary unit attached, rotatably in directions around a longitudinal axis, to an insertion section extending along the longitudinal axis in an insertion instrument. The present invention also relates to an insertion instrument including an insertion section to which the rotary unit is attached, and an insertion body assembly provided in the insertion instrument. The present invention also relates to a driving force transmitting unit which extends through an inside of the insertion section and which is configured to transmit a rotation driving force to rotate the rotary unit. Moreover, the present invention relates to an insertion device including the insertion body assembly, the driving force transmitting unit, and the rotary unit.
2. Description of the Related Art
Jpn. Pat. Appin. KOKAI Publication No. 2005-288035 has disclosed a treatment apparatus which is an insertion device that can be inserted through a treatment tool channel of an endoscope. An insertion section extends in this treatment device along a longitudinal axis. A holding section is provided to a proximal direction side with respect to the insertion section. A spiral propulsion portion which serves as a rotary unit is attached to a distal portion of the insertion section rotatably relative to the insertion section in directions around the longitudinal axis. A channel extends through an inside of the holding section and through an inside of the insertion section along the longitudinal axis. A driving force transmitting unit extends through the channel. A flexible shaft which serves as a linear portion extends in the driving force transmitting unit. When the flexible shaft rotates around a drive axis (the longitudinal axis), a rotation driving force to rotate the spiral propulsion portion is transmitted to the spiral propulsion portion. The channel is open in an opening provided to the holding section. A proximal end of the flexible shaft is connected to a motor which serves as a driving source in a vicinity of the opening. When the motor is driven, the flexible shaft rotates around the drive axis, and the spiral propulsion portion rotates relative to the insertion section.
Jpn. Pat. Appin. KOKAI Publication No. 2007-185394 has disclosed an endoscope device as an insertion device. The endoscope device includes an insertion section provided along a longitudinal axis, and a rotary unit provided in a distal portion of the insertion section rotatably relative to the insertion section in directions around the longitudinal axis. A rotation gear is provided inside the insertion section. An inner peripheral gear portion which meshes with the rotation gear is provided in the rotary unit. When the rotation gear is actuated and rotated, a rotation driving force is transmitted to the rotary unit. As a result, the rotary unit rotates relative to the insertion section. A channel extends through an inside of the insertion section. A driving force transmitting unit connected to the rotation gear extends inside the channel. The driving force transmitting unit includes a line portion extending along a drive axis. A distal portion of the line portion is connected to the rotation gear. When the driving force transmitting unit rotates around the drive axis, the rotation driving force is transmitted to the rotation gear, and the rotation gear is actuated.